1. Field of the Invention
This invention relates to security locks for slidable windows, doors and the like.
2. Description of the Prior Art
It is known to provide structures for releasably holding a window open in one of a number of positions. However, such structures are undesirably expensive assemblies wherein parts are secured together at the factory with fasteners, or are otherwise held in place by and as parts of a window assembled at a factory. Thus, in U.S. Pat. No. 3,636,660 issued Jan. 25, 1972 and entitled, "Internal Vent for Window Sash," a metal sill plate extrusion has spaced openings formed therein, and such plate is secured to the main horizontal portion of a sill extrusion. The plate and sill have aligned holes punched, drilled or otherwise formed therein, and the parts are secured together via fasteners that are inserted through the holes. A latch plunger carried on a stile of a movable sash is adapted to be lowered into locking relation in one of the openings in the sill plate extrusion. Such structures are not adapted for installation in completed buildings, i.e., the sill plate cannot be fastened to the sill of an existing window to provide the desired security.
It is also known to provide a keeper in the form of a channel bar with parallel sides telescoped into a frame extrusion during assembly of a window. Such a bar, which is disclosed in U.S. Pat. No. 3,174,194 issued Mar. 23, 1965 and entitled, "Bus Body Window," is held in place by virtue of its capture by overlapping portions in which it is telescoped, and by virtue of its ends being in abutting relation with frame portions between which the bar extends. Here, also, it is not possible to thus position such a bar in the window after it is assembled and installed.